Key Points:
-It is unclear whether myocardial viability tests should be used to guide decisions about
revascularization in patients with ischemic cardiomyopathy (ICMP).
-The randomized trial REVIVED-BCIS 2 found that for patients with severe ICMP,
multivessel percutaneous coronary intervention (PCI) plus optimal medical therapy
(OMT) was not superior to OMT alone for event-free survival or recovery of left
ventricular ejection fraction (LVEF).
-This analysis of REVIVED-BCIS 2 data asked whether myocardial viability was
predictive of event-free survival (a composite of death or heart failure hospitalization),
LVEF recovery, or positive response to PCI among ICMP patients
-No significant association was found between baseline viability characteristics for event-
free survival, LVEF recovery, or positive response to PCI. However, scar burden was
predictive of both event-free survival and LVEF recovery, and LVEF recovery was
associated with improved clinical outcomes.
Despite the intuitive presumption that dysfunctional-yet-viable myocardium will predict a
positive response to revascularization in ICMP, there is little randomized evidence that using
viability testing to guide clinical decision making results in LVEF improvement or better clinical outcomes (1). There is also conflicting evidence on whether improvement in LVEF as assessed by imaging is necessarily associated with improvement in clinical outcomes among those with re-vascularized ICMP.
The Study of Efficacy and Safety of Percutaneous Coronary Intervention to Improve Survival in
Heart Failure (REVIVED-BCIS2) was a parallel, open-label randomized trial comparing PCI
and OMT in patients with extensive coronary artery disease (CAD) and systolic dysfunction,
defined as left ventricular ejection fraction (LVEF) </= 35% (2). All patients had PCI-amenable
lesions subtending at least 4 dysfunctional but viable segments. There was no difference
between the groups in the combined primary outcome of all-cause mortality or heart failure
hospitalization (HFH) or in the individual secondary outcomes of mortality, acute myocardial
infarction, or change in LVEF at 12 months.
On March 4, 2023, Dr. Divaka Perera of Kings College London presented the results of the
Effect of Myocardial Viability, Percutaneous Coronary Intervention and Functional Recovery
On Clinical Outcomes In The REVIVED-BCIS2 Randomized Trial as a part of the Featured
Clinical Research Session of ACC.2023/WCC.
In this analysis, the baseline late gadolinium enhanced (LGE) CMR scans and serial
echocardiograms of REVIVED-BCIS 2 participants were reviewed by independent core
laboratories blinding to treatment arm, clinical information, and temporal scan sequence. A
viable segment was defined as transmural LGE <25% or contractile response during
dobutamine stress echocardiography.
This analysis sought to answer four questions. Does viability predict event-free survival? Does
viability predict improvement in LVEF? Does viability predict a positive response to PCI versus
OMT? Finally, does LVEF improvement predict event-free survival?
A total of 610 REVIVED-BCSI 2 patients were included in the analysis. Overall, 41% of the
had diabetes. Median baseline LVEF was 32%. Roughly 80% of the patients had viability
assessed via CMR, with the remainder assessed by DSE. The median number of per-patient
normal segments, dysfunctional but viable segments, and non-viable segments were 6, 5, and 5 respectively. An adjusted Cox proportional hazard was used to assess the relationship between viability and the primary outcome of death or HFH as well as in the influence of PCI on outcomes based on viability.
This analysis found that there was no association between the degree of dysfunctional-viable
myocardium and the primary outcome of event free survival (HR 0.98 CI 0.93-1.014, p=0.056).
There was also no difference in the treatment effect of PCI versus OMT by viability
characterization. However, there was an association between scar burden (per 10% increase in
scar volume) and the primary outcome, with lower scar volume associated with improved event-free survival (HR 1.18 CI 1.04-1.33, p=0.009). They also found that LVEF recovery (defined as an improvement greater than median change of 4.7%) correlated with improved clinical outcomes; those who recovered their EF at 6 months had a 38% reduction in mortality or HFH. However, if you correct the LVEF recovery for scar burden, this effect disappears.
In conclusion, this secondary analysis of REVIVED-BCIS 2 found that among patients with
severe ICMP, PCI does not improve clinical outcomes or LVEF recovery compared to OMT
regardless of baseline viability characteristics. According to Dr. Perera, there is no “sweet
spot” found for viability whereby PCI is preferred over OMT for the outcomes measured. “The
abundance of dysfunctional-yet-viable-segments was not associated with prognosis or likelihood of LV recovery; however, the scar burden was highly predictable of prognosis and likelihood of LV recovery,” Dr. Perera said. “We need to challenge the paradigm of hibernation as we have known it. There is absolutely no evidence that we should use viability to guide our decision on revascularization. Instead using scar and non-viable myocardium [to guide decision making will need to be tested in future trials.”
References
1. Ryan M, Morgan H, Chiribiri A, Nagel E, Cleland J, Perera D. Myocardial viability
testing: All STICHed up, or about to be REVIVED? Eur Heart J 2022;43(2):118-126a.
2. Perera D, Clayton T, O’Kane PD, et al. Percutaneous Revascularization for Ischemic Left
Ventricular Dysfunction. N Engl J Med 2022;387(15):1351–60.
